Presentation is loading. Please wait.

Presentation is loading. Please wait.

Evolutionary Ecology. Evidence of local adaptation.

Similar presentations


Presentation on theme: "Evolutionary Ecology. Evidence of local adaptation."— Presentation transcript:

1 Evolutionary Ecology

2 Evidence of local adaptation

3 Environmental or Genetic Variation in WesternYarrow?

4

5 Creeping Bent Grass - Agrostis stolonifera

6

7 Adaptation in Trinidad Guppies Poecilia reticulata Two males Male and Female

8 Adaptation and natural selection in guppy populations John Endler

9

10 Cline – Bergmann’s Rule

11 Bergmann’s Rule in Bears Sun bear, Spectacled bear, Brown bear, Polar bear

12 Fig. 3. Mean ± SE body size (top) and egg to adult development time (bottom) as a function of latitude for lab-reared families of yellow dung fly males and females from six different latitudinal populations in Europe, at 15°C in the sequential experiment (CH: Switzerland; GB: England; D: Germany; S: Sweden; ISL: Iceland). Blanckenhorn W U, and Demont M Integr. Comp. Biol. 2004;44:413-424 The Society for Integrative and Comparative Biology

13 Cline – Allen’s Rule Arctic Cool Temperate Warm Temperate Desert

14 White clover – Trifolium repens

15 Cline in cyanide production by white clover – dark circle populations with cyanide; white circle lack cyanide

16

17 Clinal variation in gulls Herring GullLesser Black-backed Gull

18 What is a species?

19 Morphological species concept: Assemblages of individuals with morphological features in common and separable from other such assemblages by correlated morphological discontinuities in a number of features. from Davis and Heywood

20 Rubus - Blackberries

21 Biological Species Concept Comte de Buffon Ernst Mayr

22 Biological species concept A species consists of a groups of organisms which can sexually interbreed or at least have the potential to sexually interbreed (if geographically isolated) that are reproductively isolated from other such groups. This is based on two criteria: 1. do populations from the same locality normally interbreed? 2. if cross-fertilization does occur, are the hybrids viable and fertile?

23 Sibling species Species which look almost identical morphologically but which do not interbreed. Drosophila pseudoobscura

24

25 Gilia angelensis Gilia tricolor

26 Polytypic species Species made up of populations which differ morphologically but which will interbreed in nature.

27

28 Variation in Song Sparrows

29 Potential problems with biological species concept Fossil species cannot be tested for reproductive isolation Asexual species also cannot be test for reproductive isolation – each clone is genetically separate from all others – Mayr calls asexual species ‘paraspecies’

30 Phylogenetic species concept Species are defined based upon branching patterns in phylogenetic trees. Species are also defined based upon differences in evolutionary history. Species typically diverge when reproductively and/or geographically isolated.

31

32 Western and Florida Scrub Jay

33 Speciation Speciation is the formation of new species. Allopatric speciation - formation of new species occurs when populations of a species become geographically separated from each other and diverge so that when they co-occur they cannot interbreed. Sympatric speciation - occurs when reproductive isolation occurs within the range of a population before any differentiation of the two species can be detected.

34 Allopatric Speciation – Galapagos Islands Finches

35

36

37 Darwin’s Finches

38 Sympatric and Allopatric Speciation – Picture Winged Drosophila

39 Eight Species of Picture- Winged Drosophila

40 Founder Events with Picture Winged Drosophila

41 Sympatric Speciation in Cichlids

42 Variation in Lake Malawi and Lake Tanganyika Cichlids

43 Polyploidy in Spartina cordgrasses Polyploidy - an increase in the number of chromosomes beyond the typical diploid number - may be a doubling or greater - this happens most often in plants Polyploidy often occurs following the production of hybrids

44 Spartina alterniflora marsh – North Carolina

45 Spartina alterniflora

46 Spartina maritima

47 Spartina x townsendii

48 Spartina anglica

49 Spartina anglica – invasive in New Zealand


Download ppt "Evolutionary Ecology. Evidence of local adaptation."

Similar presentations


Ads by Google